Cytotoxicity caused by near-ultraviolet-irradiated soluble vitamins
Project/Area Number |
04807073
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Research Category |
Grant-in-Aid for General Scientific Research (C)
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Allocation Type | Single-year Grants |
Research Field |
Dermatology
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Research Institution | Osaka University |
Principal Investigator |
SATO Kenji Osaka University School of Medicine, Department of Dermatology, Associate Professor, 医学部, 講師 (00116039)
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Project Period (FY) |
1992 – 1993
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Project Status |
Completed (Fiscal Year 1993)
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Budget Amount *help |
¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1993: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1992: ¥300,000 (Direct Cost: ¥300,000)
|
Keywords | Near Ultraviolet Light / Cytotoxicity / Riboflavin / Pyridoxine / Oxygen / Hydrogen Peroxide / Active Oxygen Species / Fibroblast / 長波長紫み線 / 色素性乾皮症 / 種痘様水疱症 / 繊維芽細胞 |
Research Abstract |
Near-ultraviolet light (UVA) has received much attention as a possible cause of skin aging and carcinoma. The study focused on the role of photoinduced cytotoxicity of endogenous substances, riboflavin and pyridoxine, which have absorption spectra in the UVA range. These soluble vitamins were found to become cytotoxic after UVA.The cytotoxicity lasted for a long time after irradiation. Thus, the cause of the cytotoxicity was thought to be stable photoproducts derived from the vitamins and/or hydrogen peroxide. The production of hydrogen peroxide after the irradiation of soluble vitamins was studied by the use of horseradish peroxidase (HRP). Its absorption peak at 400 nm shifts to 417 nm after its binding to hydrogen peroxide. Irradiated pyridoxine produced a little amount of hydrogen peroxide which, however, was not cytotoxic. Thus, the cause of pyridoxine photosensitization was thought to be stable photoproducts. On the other hand, a high concentration of hydrogen peroxide was produced in UVA-irradiated riboflavin solution. Photoinduced riboflavin cytotoxicity was eliminated by catalase treatment of the irradiated solution. This shows that the cytotoxicity was mostly caused by hydrogen peroxide. The cytotoxicity of irradiated soluble vitamins was studied under anaerobic conditions. In the case of pyridoxine, its cytotoxicity decreased because of slow down of its photo-degradation. In the case of riboflavin, its cytotoxicity increased dramatically. The increase was thought to be due to short-lived active oxygen species.
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Report
(3 results)
Research Products
(9 results)